I had a forum member recommended to me because she was told she needed a new gearbox by the Fort Worth dealer and Jag Mac in Dallas. They scanned the car and the list of faults was impressive. They did not look at the car other than scan for DTCs and concluded the gearbox was TOAST.

She got the car to me and I scanned it also. I lifted the car in the air and saw a drip,drip of fluid on the floor.

The plastic pan was warped/leaking so I told her to leave it and I would get the pan/filter/fluid replacement, then the fluid level correct.

The car shifted better but there were still issues. The low fluid level allowed the trans to learn REALLY BAD HABITS. I cleared adaptations but the ECM needed updated software also. I ran the erase/update and took the car for a drive.

Everything back to normal!!!!!!!!!!!!!

A few hours labor and a few hundred dollars in parts and she was back on the road. That was about 5 years ago. She calls every few years for service but she is 50 miles away so I understand the infrequent visits.

A replacement gearbox would ALSO have fixed her problem, just alot more money.

DIAGNOSE,DIAGNOSE,DIAGNOSE,DIAGNOSE,DIAGNOSE,DIAGN OSE,DIAGNOSE,DIAGNOSE,

My Motto.......Stop throwing parts at the problem as a FIRST resort.

bob

 

I think I missed the answer but did you refill using the proper procedure (engine running etc)?

 

But the dealer LIKES doing that....

 

Some at the dealer likes doing that.
I diagnosed the problem before replacing parts when I was there.

Not everyone at a dealer is a 'parts-changer'.

Some of us are ACTUALLY MECHANICS.

bob

 

I'm sure that's so. But how does the ordinary car owner tell? (Whereas most indy guys seem good and as it happens charge a bit less, not having the big overheads of most dealers.)

 

Hey Lads,

Just an update as I have not done anything else yet.
What I did do today was take the car to my shop and they read the codes on the transmission for me as of today. The information is not good but maybe there is one piece of info that might shed some light?

My shop has really good guys with a lot of experience but they aren't a NASA laboratory so sometimes I have to take what they say with a grain of salt until I prove to myself that everything they say makes sense.

Generally, they feel that the renewed transmission fluid change on a car that has done 120k has basically washed up the transmission and cleaned out all the particles that were keeping it moving. They said that they have seen this before with a customer who wanted to change the fluid in a car with lifetime fluid and over 100k. They did as was asked and the fluid that came out of the vehicle (I believe BMW) was extremely dirty and they felt good about servicing it. After a couple of weeks, the customer reported back that the tranny was toast and wouldn't go into either drive or reverse. After some investigation they ended up having to replace the transmission with a rebuilt unit. So as I have said, grain of salt right now because I have a lot of resources like yourselves to help me make smart choices on repairs. Not going to put a rebuilt transmission into this car until every other stone has been turned. They feel that the clutch plates are all worn out.

Now remember what I had going on before the transmission fluid change. The car was fine except for the little bump I would feel going from 2nd to 1st like rolling up to a stop light or sign. After the fluid change is when all the issues started. So the last time we read the codes we only reported the 5th gear ratio DTC coming from the transmission. Well it seems to be getting worse now as the code list has grown. Feels like this transmission is working its way to the bottom on me quickly.

Amongst some other codes pertaining to engine running, here were the codes stored for the transmission

P0730 - Incorrect gear ratio
P0720 - Output speed sensor circuit malfunction
P0733 - Gear 3 incorrect ratio
P0735 - Gear 5 incorrect ratio
P0729 - Gear 6 incorrect ratio

As stated, the last time we checked and cleared the codes, we only had the P0735 code.

My shop thinks that the clutches are all slipping.
Its dire right now and I do plan to do some more research, get the TCM adaptations renewed, hopefully do the computer update if it hasn't been done already, check the fluid level to be certain and anything else I can try before I throw in the towel. If I have to rebuild this transmission after this, I am going to be very fearful of using any transmission fluid suggested outside the manufacturers specification regardless of the cost saving because that, to me is the unknown here.

 

The problems are so major, it feels like the cause has to be something simple. So, all of a sudden, ALL clutches have given up the ghost? From a distance (and the comfort of my chair), it is hard to believe, but what do I know...

When you did the fluid change, did you mess with the wiring connector on the transmission? It is surrounded by a sleeve with o-rings that often leak, so it is considered a maintenance item. My understanding is that it is possible to put the electrical connector back on in a manner that pushes the pins back in too much, and cause connectivity issues. Further, the sleeve has to be put in without twisting. The electrical plug from the harness has to end up within a fixed distance from the case. Finally, the plug has to be locked in place with some form of twist. There are great reads here:

6_speed_sleeve_replacement.pdf

Separately, you need to find some time to check the reluctor ring on the driver side rear wheel before you spend any real money. It is technically part of the ABS system, but provides wheel/road speed to the whole shifting logic. If it is loose, it reports a speed that is inconsistent with the output shaft speed, and throws all kinds of errors. You definitely need to eliminate this as a cause of your problems. Put the rear of the car on ramps, and gently pry the ring with a screwdriver. Anything other than solid with the axle is a problem.

Best of luck, keep us posted.

 

Thank you for this.

I can honestly say that nothing was touched in regards to a sleeve. Is it possible that the sleeve could be the issue? I never touched it and only changed the filter and the fluid. Should this have been serviced when doing the filter and fluid service?

For sure, I am going to check everything possible that doesn't close in on the price of another transmission.

Yes, its scary how quickly the transmission has declined since the fluid and filter change. The P0730 code is the heartbreaker right now because that basically means - your transmission is toast. Not much other dialog about it than that.

The transmission has not been abused in the slightest since I received the car. As a matter of fact, its been babied to the point of being an obstacle merging on the freeway to avoid any kick-downs. I got the car for cheap enough that even if I rebuild the transmission or replace it with a low mileage unit, it won't be devastating. My shop says they will do the swap for 400.00 including fluids so that is pretty incredible if you think about it. But they are also friends and I have helped them research out some issues on the forums for things they were struggling to understand. Guess I paid into the karma bank

Used transmissions can be had for between 1000-2000 bucks some with pretty low mileage so I think for around 2200, I can have it swapped out. Just not going there until I research the **** out of this and do everything I can before throwing in that towel. So any ideas at this juncture are certainly going to be looked into.

It will help us all tremendously if I discover something outside of having a bad transmission period.

 

Check the pdf I referred to above. It has great pictures. I suppose there is an off chance that cleaning up and re-seating that connector could help.

Just to ask, are you positive you used Mercon "SP"? I believe there is also a MERCON "LV", which looks attractive, but is actually not suitable for the 6HP26.

Last, are you positive the right procedure was used for refill? This is detailed here, and involves filling the transmission, engine running, until a temperature is reached and fluid drips out:

jaguar-6hp26-6hp28-transmission-fluid-level-procedures

If not, you might be running way low on fluid...

 

The general rule on these ZF 6HP26 units is that if you decide to drop the pan, you should replace the factory sleeve before installing a new pan/filter. The original sleeves tend to eventually develop leaks. The new-and-improved sleeves are supposedly much better. When we dropped the pan on my wife's 2006 XK8 in July 2013, we replaced the factory sleeve with a new-and-improved one. The car has had two different drain-and-fills with Mercon SP since then. No pan drop on either one of those....

My 2005 S-Type has also had two different drain-and-fills with Mercon SP. We never dropped the pan on this car so we never changed the sleeve. Now at 98,400 miles, the factory sleeve has held tight thus far and I'm keeping my fingers crossed that it will continue to do so throughout my ownership period of this car. Time will tell....

 

Yes, great photos indeed!

Yup, 100% certain the fluid was Mercon SP. Had to drive halfway across town to get it and the box still sits in my garage - just put eyes on it.

And again yes, I did the service exactly as specified.
I already had experience with this as my sons VW New Beetle has a transmission service that is almost identical to the Jags. Level, requiring temp probe for specific temp range at final top off, etc.

Fluid was between a very thin stream and drips when I put the plug back in. Gears had already been cycled through a number of times and the temps were dead on in the middle of the prescribed range.

Not going to say I didn't have a bit of tranny fluid all over my hands, forearms by the time I was done though. Hot exhaust pipes, cramped spaces and awkward angles are no fun.

Having said that, I am still going to have this double-confirmed at my shop so we can have access to the lift. Probably will just go ahead and pull the pan again and replace the sleeve too but want to check that fluid level first. Move on from there.

 

Copy that!

I guess the question that would need to be answered here is if the sleeve not being changed and leaking for whatever reason would cause this level of serious decline in an otherwise good transmission? Don't expect you to know the answer, just thinking out loud.

 

I doubt it, but a leak is a leak, so, over time the lower fluid level would become a concern (when you think about it, the trans needs to work going uphill, and under braking, too so the level can't be THAT critical during normal driving). If it is leaking, the back side of the transmission becomes wet. This is the general area where the transmission output flange meets the driveshaft. I assume that if it was leaking, you would have seen it during the fluid change. The plug is fairly high, so it does not leak very much at all.

Come to think of it, is there any sign now that there is a leak? Is the plastic pan wet with fluid anywhere? There is an off chance the gasket was pinched during replacement, and the new fluid is leaking out. Unlikely, but a thing to check.

 

Nah, tight as a bug in a rug.
Parked in my neighbors very clean and unmolested driveway so it better be lol.

At the same time, I also swapped out all of the T27 to T40 Torx and used a Torque wrench to set everything. Not even a residue under there.

 

Quick update as I haven't been driving the car lately. I had to get the brake pedal switched replaced which I did today.

So I took the car out for a quick run to see if I was still getting the rear lights, cruise warning and happy to say that's all good now. While on the drive the transmission kinda felt the way it had all along with the little bump into first and some weirdness in the way it upshifts. Kinda like its not sure what its supposed to do in the next gear. I will shoot a quick video tomorrow to show you what I mean.

So then I did something different and put the car in manual mode. I just wanted to see if I could get gears to slip if the clutches are indeed wearing out. I can tell you that they didn't slip. The first to second transition felt a little weird like it has been but then it was all mean on the shifter from 2nd gear onward. I went around a long block a number of times and literally put the boots to the car. Each round got more and more aggressive until the last go around where I put the thing sideways coming onto my back road with tires smoking. As long as I was in second and up, it seems the transmission hauls ***. Will do some more driving tomorrow but this is making me think that there might be some issues in the solenoids? Maybe they didn't particularly like the cleanup of the fluid.

I will shoot some video in the car tomorrow so you guys can get a sense of what it is that I have going on here.

B

 

Issue has been resolved - please see this thread

https://www.jaguarforums.com/forum/x...-intel-203967/